The NaPTAN schema is a UK national de facto standard sponsored by
the UK Department of Transport and supports both the public registration of bus
timetables by the Vehicle and Operator Services Agency (VOSA), and the data
collection for the Transport Direct Portal. NaPTAN includes on a related
standard - the National Public Transport
Gazetteer.

The NaPTAN database is maintained centrally under contract to the Department
of Transport by Landmark.

Summary

There is a new 2.5 Release available or an enhanced version of the NaPTAN schema.

The current version of NaPTAN is Version
2.4. Version 2.1 and 2.4 are still in widespread use.
Versions are backwards comaptible, that is 2.1 documents will validate against a 2.4 schema